1. Field of the Invention
Stereoscopic Apparatus and Method of Using Same.
2. Description of the Prior Art
A number of optical systems have been developed in the past to produce stereoscopic views of a scene. The most practical methods employ means to produce individual records which were made from two laterally displaced positions, generally 2.5 inches apart. This distance corresponds roughly with the human interocular. The records are viewed by suitable means whereby the right eye sees only the right record and the left eye sees only the left record. The resulting effect is a stereoscopic perspective view of the scene. It is important to understand that each of the two records is different from the other by virtue of position relative to the eyes of a human in order that a true stereoscopic view of the scene be presented to the brain. The majority of inventions produced have dealt with methods to record and present these two distinct records to each eye for viewing. Generally, two methods are used to carry out the stereoscopic technique. One method uses separate picture taking means such as separate cameras. Then separate viewing means are used. The other method is a variation on the first which may utilize a composite technique at any of various points in the process. As an example, a single camera may be equipped to make both records or a single strip of film may be used, or in the case of a television system, a picture tube is used to present the separate views with suitable optical means to channel each record to the appropriate eye.
Several problems are common to all methods. Unique distortions not found in two-dimensional technique may be created at any point in the stereoscopic process so as to present a stereoscopic view of the scene of improper perspective. Most notable are those distortions produced by unequal optical paths to each record, improper camera interaxial IE, lens separation, poor vertical registration, and cross-talk, a condition whereby each eye may also see part of the image intended for the other eye. Varied amounts of these distortions seem to greatly affect the quality of the stereoscopic view.
The most popular method of composite film or television recording means has been the application of a prism or mirror assembly in front of the lens of a single camera. The prisms or mirrors present two distinct and separate views of the scene to the lens. The apparent viewing positions may be spaced about 2.5 inches apart. The image presented to the lens may be a coded composite view such as achieved by the application of filter means, or the image may be two adjacent views spaced laterally or vertically. The particular problems with this technique are that the image may suffer from unequal path lengths which make one record appear as though it was made at a point closer to the scene. This is a very noticeable distortion. Also, only lenses of moderate to long focal length can be used due to the limited aperture of the front reflector optics.
A primary object of the present invention is to provide a lens assembly that may be mounted on a conventional camera used in producing two dimensional views and transform the latter to one in which each of the stereoscopic records is of substantially the same size, and the invention employing lenses of short focal lengths such as used in normal production without vignetting the record.
Still another object of the invention is to provide a method of adjusting horizontal displacement of the aforementioned record pairs relative to each other, thereby providing convergence adjustment means to the camera operator so as to control the degree of relief in the picture, said adjustment means allowing the taking of stereoscopic pictures that may be viewed in three-dimensions with suitable filter means or as simultaneous conventional two-dimensional pictures.
It is yet another object of the present invention to provide a system of three-dimensional color television signals.
Still another object of this invention is to provide adjustment means to control the ratio of luminosity of each record to the other so as to provide a color rendition of wide spectral range and deep saturation not possible with previous composite color three-dimension methods.